The subgroup separability of free products of two free groups with cyclic amalgamation

A lubricant for use in the processing of plastics is disclosed. The lubricant comprises a polyalkylene oxide made from a monomer selected from the group consisting of aliphatic, non-substituted, 1,2-alkylene oxides containing from about six to about 40 carbon atoms, and mixtures thereof, said polyalkylene oxide having an average molecular weight from about 1,000 to about 6,000. Also disclosed is a process for using such lubricants in the shaping of thermoplastic polymers.